(1,a,A)
(1,a,B)
(1,b,A)
(1,b,B)
(2,a,A)
(2,a,B)
(2,b,A)
(2,b,B)

If you want the list generated at once, you could use the following snippet by merlyn. If you want an iterative solution, you could use the following. A benefit being that it should work in relatively constant time no matter how big the arrays are.


my @aoa = (
    [1,2],
    ['a','b','c','d'],
    ['A','B','C'],
);


my $iter = make_aoa_iterative(@aoa);


while (my @els = $iter->() ){
    print @els,"\n";
}


sub make_aoa_iterative {
    my @arefs = @_;
    my @arrayindexes = ();
    foreach (@arefs){
        push @arrayindexes,[$_,0,$#{$_}];
    }
    
    return sub {
            return if $arrayindexes[0]->[1] > $arrayindexes[0]->[2]; 
            my @els =  map { $_->[0]->[ $_->[1]] } @arrayindexes;
            # Check for out of bounds....
            $arrayindexes[$#arrayindexes]->[1]++;
            for (my $i = $#arrayindexes; $i > 0; $i--){
                    if ($arrayindexes[$i]->[1] > $arrayindexes[$i]->[2
+]){
                        $arrayindexes[$i]->[1] = 0;
                        $arrayindexes[$i-1]->[1]++;
                    }else{
                        last;
                    }
            }
            return @els;
            
    };
}
[download]

---

Update
I'm formal-math challenged. Is this formally a permutation? If someone could clarify, I'd appreciate it.

-Lee

"To be civilized is to deny one's nature."

Yeah... that's does the trick. I had been working on a version that didn't calc all possible indexes beforehand (but now I'll stop). I'll try calling it "a function that returns all possible vectors in a discrete n-dimensional space." It that trekkie enough?